The skull is composed of distinct bony plates that come together at joints called sutures that allow little or no movement, especially in adults. The joints between teeth and their sockets, called gomphoses, also allow very little movement.
At and before birth, the human skull, or cranium, is composed of several distinct bones that are held together with fibrous bands of tissue called cranial sutures. These bands allow the cranium to deform during childbirth with minimal risk of injury to either the child's brain or the mother. They also permit the cranium and the brain within it to continue growing after birth. As children grow out of infancy and the cranium approaches its adult size, these bands gradually turn into bone, and several of the bones fuse together. Even in adulthood, the seams between some cranial bones typically remain, with the bones being interlocked in a fashion that permits little or no movement.
Teeth are not technically bone, but the connection between teeth and their sockets is also described as a joint. While some slight movement occurs when chewing and when braces adjust the positions of teeth, this is negligible in comparison with more typical movable joints. These joints, called gomphoses, are another example of immovable joints
All joints in the skull are immovable except the temporomandibular joints, which allow the lower jaw to move up and down.